[Hallicrafters] knob retaining screws

[rbethman]

Well, there I go - learning again!

*I* have not run across the four spline knobs YET!

But I like Roy's solution!

Bob - N0DGN

Roy Morgan wrote:
> At 12:37 PM 10/4/2007, you wrote:
>> ... set/grub screws holding knobs on
>> that are not allen or slotted screw, they seem to be 4
>> sided. What type are they
>
> Douglas,
>
> They are four-slot BRISTOL spline set screws.  I am working on an 
> SX-88 which uses:
>
> the six-flute .096 inch spline screws in:
>  - the band switch shaft couplings
>  - the band switch knob
>
> and four-flute smaller diameter spline set screws in most other places 
> (Including the gearbox, which I have completely dis-assembled.)
>
> The place to get *genuine* Bristol Wrench Company USA produced, 
> highest quality tools is at Max Gain Systems.  I recently got long 
> L-wrenches in three sizes for about $2 each.   If you call now, they 
> would be in the mail to you tomorrow, or maybe today:
>
> Max-Gain Systems:
> http://www.mgs4u.com/Bristol-spline-L-keys.htm
> 221 Greencrest Ct., Marietta, GA 30068-3825
> Phone: (770) 973-6251
> Fax: (815) 461-7730
> Email: <mailto:info at mgs4u.com>info at mgs4u.com
>
> These folks have straight wrenches chucked in screwdriver handles, one 
> for each size, short arm and long arm individual wrenches, and kits.  
> Their SS-508 kit is likely to do all you need, and is priced at $14 
> plus $2 sh.
>
> They have a special to get a very nice allen wrench kit in addition 
> for a modest amount more. "Special combination price! The HS-206 if 
> purchased WITH the SS-508 Bristol spline L-key kit are priced at 
> $18.95 plus $3 shipping in US and possessions, $4 worldwide. Ask for 
> the "HS-206 combo". "
>
> There are two sizes of 4-flute set screws you may have run into:
> S-069-4, or S-076-4
> The three digits in the middle are the size in thousandths of the 
> outer diameter of the wrench:  I suspect it is the S-076-4 that you 
> need.  If you intend to order only the minimum to get you covered, 
> discover the size of an allen wrench that seems like it should fit.  
> (Note that allen wrenches are sized from flat to flat, not max outer 
> diameter.)
>
> R-390 receivers use the 6-flute .096 size.
> HP instruments with very small knobs use the smaller or smallest 
> 4-flute size.
>
> I have three suggestions:
>
> 1) Do not order from Snap-On. You'll pay as much for one wrench as you 
> do for all you need from Max-Gain.  Do not go down to Sears or any 
> other place looking for these - they don't have them.
> 2) order from Max-Gain and get the best available
> 3) break the sharpness of the end of the wrench with a very fine 
> sharpening stone to make it easier to get it into the set screw
>
>
> The Xcelite 99-series wrench inserts with handles (Tee and screwdriver 
> type) are very good also.  They make a kit with handle, extension, and 
> nine wrench inserts.  Mouser lists these inserts as individual parts 
> but most of them are described as "discontinued".  The Xcelite tools 
> are not discontinued by Xcelite, or their distributor which is:
>
> Cooper Tools apparently supplies Xcelite sets to retailers:
> Cooper Tools, Inc (Xcelite):
> http://www.cooperhandtools.com/brands/xcelite/index.cfm
>
> Another source is:
> Newman Tools, Inc.:
> http://www.newmantools.com/hand/splinekey.htm
>
> Call Max-Gain now.